Di-substituted beta-phenethylcarbamic acid esters

ABSTRACT

Novel di-substituted Beta -phenethylcarbamic acid esters. The compounds are useful as antidepressants and anti-Parkinsonism agents.

United States Patent [111 3,869,492

Biel et al. Mar. 4, 1975 [54] Dl-SUBSTITUTED [58] Field of Search 260/463 BETA-PHENETHYLCARBAMIC ACID ESTERS [56] References Cited [75] Inventors: John Hans Biel, Lake Bluff, lll.; UNITED STATES PATENTS Klund" Brookfield 3.793.342 2/1974 Kaiser et al. 260/471 6 [73] Assignee: Aldrich Chemical Company,

Milwaukee, Wis. Primary E.\-nminer-Lorraine A. Weinberger Assistant E.\'aminerL. A. Thaxton [22] Flled' 1973 Attorney, Agent, or FirmRobert L. Niblack; Joyce R. [21] Appl. No.: 385,009 Krei; Vincent A. Mallare Related US. Application Data [62] Division of Ser. No. 96.586. Dec. 9, 1970, Pat. No. [57] ABSTRACT 3.801.624. Novel di-substituted B-phenethylcarbamic acid esters.

The compounds are useful as antidepressants and anti- [52] US. Cl. 260/463, 260/347.4, 260/455 B, Parkinsonism agents,

260/471 C, 424/285, 424/301 I 51 int. Cl. C07c 125/06 4 Clam", Drawmgs DI-SUBSTITUTED BETA-PHENETHYLCARBAMIC ACID ESTERS CROSS REFERENCE TO RELATED APPLICATIONS This is a division of application Ser. No. 96,586, filed Dec. 9, 1970, now [1.8. Pat. No. 3,801,624, issued Apr. 2, 1974.

BACKGROUND OF THE INVENTION Until recently, patients suffering from Parkinsonism were treated with anticonvulsants, antispasmodics, central nervous system stimulants, and the like, in an attempt to produce temporary amelioration of their complaints. In severe cases, surgical procedures were employed with some success. L-Dopa was the first single agent found to be effective in reversing the akinesia and rigidity of Parkinsonism, particularly in severe cases. An increase in mental alertness and wakefulness. relief from depression, and an increase in intellect has also been observed in patients receiving L-Dopa.

While L-Dopa has produced some rather promising results in experimental therapy and is being used in a limited number of patients, it is not well tolerated by a number of patients. The most frequent side effects are nausea, vomiting, postural hypotension, cardiac dysrhythmia and choreiform movements. The abnormal, involuntary movements pose severe problems to the drugs continued use in approximately 50 percent of the patients. Furthermore, dopamine itself is not orally active and has a very short duration of action. Thus, the search for more effective, orally-active, long-acting anti-Parkinson agents continues. It is an object of the present invention to provide such agents.

SUMMARY This invention relates to novel di-substituted B-phenethylcarbamic acid esters represented by the structural formula:

wherein: R and R are hydrogen, benzyl, substituted benzyl, or

wherein A is O, NH, or S, and R is lower alkyl, lower alkenyl, or lower alkynyl; and R is lower alkyl, lower alkenyl, lower alkynyl, lower haloalkyl, cyclopropylmethyl, ,8-(2-furyl)-ethyl or azetidinyl; with the limitation that when A is O and R is ethyl, R cannot be ethyl, and when R, and R are benzyl, R cannot be methyl.

The presently preferred compounds for treating Parkinsonism are those wherein R is hydrogen or benzyl; R is hydrogen or benzyl; and R is ethyl or trichloroethyl, and A is O.

The term lower alkyl as used herein refers to both straight and branched chain C -C alkyl groups including methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, iso-butyl, n-pentyl, iso-pentyl, neo-pentyl, and the like.

Lower alkenyl refers to both straight and branched chain alkenyl groups containing from 2 to 5 carbon atoms, such as vinyl, allyl, methallyl, l-pentenyl, and the like.

Lower alkynyl refers to C -C alkyl groups as defined above from which two hydrogen atoms have been removed from each of two adjacent carbon atoms to produce acetylenic unsaturation; e.g., propargyl, 2- butynyl, l-pentynyl, and the like.

Substituted benzyl" refers to a mono-, di-, or trisubstituted benzyl moiety substituted in the ortho, meta and/or para positions by a chloro, fluoro, iodo, bromo, or trifluoromethyl atom.

Halo" includes chloro, fluoro, bromo, an iodo.

The anti-Parkinson activity of the above compounds was established using the Harmonyl (deserpidine) Antagonism Test. In the Harmonyl test, mice are dosed orally with 50 mg/kg of deserpidine 24 hours prior to drug evaluation. In mice, deserpidine produces ptosis, hunched posture, sedation, catalepsy and rigidity. L- Dopa produces marked reversal of the above effects in mice. Antagonism of the deserpidine effects in mice are graded slight ('1), moderate (2) or marked (3), based on the reversal of the Harmonyl effects. The compounds of the invention produce moderate to marked reversal in dosages of from 10 to 200 mg/kg of body weight.

The compounds are generally administered to mammalian Parkinsonism patients in dosages of from 10 to 200 mg/kg of body weight daily, preferably in divided doses. While the compounds exhibit both oral and parenteral activity, the preferred route of administration is the oral rgute, The oral LDfiQ'flq of the compounds of this invention in mice are approximately 600-1,000 mg/kg.

The antidepressant activity of the compounds of this invention was first established in the modified dopa test as described by Everett, et al., Fed. Pr0'c., 23 p. 198 (1964). The compounds are useful as antidepressant agents when administered to depressed patients in dosages of from 10 to 200 mg/kg of body weight daily, preferably in divided doses.

Representative compounds of the present invention include 3,4-Dibenzyloxy-B-phenethylcarbamic acid, furfuryl ester,

3,4-Dihydroxy-B-phenethylcarbamic acid, ethyl ester,

3,4-Dihydroxy-,B-phenethylcarbamic acid, isopropyl ester,

3,4-Dihydroxy-fiphenethylcarbamic acid, n-butyl FEB... A i

3,4-Dibenzyloxy-B-phenethylcarbamic acid, ,B-trichloroethyl ester, 3,4-Dibenzyloxy-fi-phenethylcarbamic acid, isopropyl ester,

3,4-Dihydroxy-B-phenethylcarbamic acid, trichloroethyl ester, 3,4-Dihydroxy-B-phenethylcarbamic azetidinyl ester, 3,4-Dibenzyloxy-B-phenethylcarbmic acid, cyclopropylmethyl ester, 3,4-Dithioethoxycarbonyl-B-phenethylcarbamic acid, ethyl ester, 3,4-Dimethoxycarbonyl-B-phenethylcarbamic acid,

methyl ester,

acid, 3-

3 3,4-Dipropargyloxycarbonyl-B-phenetnylcarbamic acid, propargyl ester, 3,4-Diallyloxycarbonyl-B-phenethylcarbamic allyl ester.

acid,

purified by a Kugelrohr distillation to give 14 g (78 percent) of 3,4-dibenzyloxy-B-phenethylisocyanate as a light yellow oil, b.p. 180 (0.05 mm).

The method of synthesis of the compounds of this in- Analysis CalcdforC H NO-z C 76.86 H 5.89 N 3.90

w r 2:1 21 .1 v 1 4 vention is represented by the follo mg eact 11 Found: CWJRHSHN'HO scheme.

R10 CH2CH2NHCOR4 Analysis Calcd. Found PDLNO. R1 R1 R1 M.P. Empiricaliormula C H N C H N 5 II H (CH:1)1CH 91.5-92.5 ClzHflNOl 60.25 7.11 5.86 60.13 7.25 5.77 II H OClaCHz 155-157 CnIIflChNO I 40.21 3.68 4.12 40.38 3.84 4.14

4 H H 118-119 C1aHi7NO4 62.07 6.81 5.57 62.20 6.51 5.59

-o1n 5 11 H 102-104 C14H1oNO1 63.42 7.7 5.28 63.40 7.99 5.71

6 11 (T 04115 127-129 CnHwNOo 56.64 6.40 4.71 56.71 6.44 4.60

CzHsU- 7 (1111150114 0111150114 01120014 127.5128.5 C2sHz1C1NO1 59.61 4.75 2.75 59.16 4.63 2.88 s 011150112 011150112 011(0113): 80-83 CZflHflDNO l 74.44 6.97 3.34 74.66 6.89 3.41 9 011156114 011150112 71-73 CzaHzaNOa 73.36 6.11 06 73.36 5.97 3.1

which can be converted to 7(A=O, NH or S) by treat-- ing 6 with either an appropriate chloroformate or an isocyanate.

The following examples further illustrate the present invention.

EXAMPLE I PREPARATION OF 3.4-DIBENZYLOXY-B-PHENETHYLCARBAMIC ACID, ISOPROPYL ESTER A. 3,4-Dibenzyloxy-B-phenethylisocyanate In a 500 ml three necked flask equipped with a gas inlet tube and a Claisen head for distillation were placed 18.5 g (0.05 mole) of benzyloxydopamine hy-' drochloride in 350 ml of toluene. This was heated to reflux and 150 ml of toluene distilled off. The Claisen head was replaced with a reflux condenser equipped with a drying tube and phosgene was bubbled through the refluxing solution for four hours. The reaction was allowed to stand at room temperature overnight, filtered, and solvent removed in vacuo and the residue B. 3,4Dibenzyloxy-,B-phenethylcarbamic acid, isopropyl ester In a 50 ml flask equipped with a magnetic stirrer and a reflux condenser protected by a drying tube were placed- 4.5 g (12.5 mole) of 3,4-dibenzyloxy- Bphenethylisocyanate, 20 ml of benzene, 1.3 ml of dry isopropanol and a crystal of bicyclo[2,2,2]1,4-diazaoctane. The reaction was heated at reflux for 20 hours. Removal of the solvent left a residue which contained the unreacted isocyanate. The residue was redissolved in 25 ml of benzene, 1.3 ml of isopropanol added and 2 drops of DBU (Aldrich-1,3- diazabicyclo[5,4,01undec-5 ene) added. This was heated to reflux for 24 hours. The reaction was cooled, diluted with 25 ml of benzene, filtered and the solvent was removed in vacuo. The residue was dissolved in 150 ml of hot cyclohexane and set aside to crystallize. The white solid was filtered off and dried in vacuo to yield 2.1 g of 3,4-dibenzyloxy-B-phenethylcarbamic acid, isopropyl ester, m.p. -83C.

Analysis Calcd. for C ,,H NO C, 74.44; H, 6.9 Found: C, 74.68; H, 6.8

EXAMPLES 2 9 The following compounds were prepared according to the method of Example 1 by replacing isopropanol with the appropriate alcohol.

EXAMPLE 10 3,4-DIHYDROXY-B-PHENETHYLCARBAMIC AClD, ETHYL ESTER A solution of 45 g of 3,4-dibenzyloxy-B-phenethylcarbamic acid, ethyl ester, prepared according to the method of Example l, in 200 ml of ethanol containing 3 g of moist l0 percent Pd/C was hydrogenated at 40 p.s.i. The reaction was filtered, evaporated to dryness and recrystallized from benzene to yield 18.4 g of product, m.p. 99-l0l.

Analysis Calcd. for C,,H, ,NO,: C, 58.65; H, 6,7l; N, 6.22 Found: C, 58.63; H. 6.58, N, 5.98

The compounds useful in the practice of the present invention are generally formulated into pharmaceutical compositions comprising, as an active ingredient, at least one of the active agents in association with a pharmaceutical carrier or diluent. The compounds useful in the practice of the invention exhibit both oral and parenteral activity and can be formulated in dosage forms for oral or parenteral administration.

Solid dosage forms for oral administration include capsules, tablets, pills, powders and granules. In such solid dosage forms, the active compound is admixed with at least one inert diluent such as sucrose, lactose or starch. Such dosage forms can also comprise, as is normal practice, additional substances other than inert diluents, e.g., lubricating agents such as magnesium stearate. In the case of capsules, tablets and pills, the dosage forms may also comprise buffering agents. Tablets and pills can additionally be prepared with entericaqueous solutions, suspensions or emulsions. Examples of non-aqeuous solvents or vehicles are propylene glycol, polyethylene glycol, vegetable oils, such as olive oil and injectable organic esters such as ethyl oleate. Such dosage forms may also contain adjuvants such as preserving, wetting, emulsifying and dispersing agents. They may be sterilized by, for example, filtration through a bacteria-retaining filter, by incorporating sterilizing agents into the compositions, by irradiating the compositions, or by heating the compositions. They can also be manufactured in the form of sterile solid compositions which can be dissolved in sterile water, or some other sterile injectable medium immediately before use.

The dosage of active ingredient in the compositions of this invention may be varied; however, it is necessary that the amount of the active ingredient shall be such that a suitable dosage form is obtained. The selected dosage depends upon the desired therapeutic effect, on the route of administration, and on the duration of the treatment.

We claim:

1. A compound of the formula wherein R is hydrogen or O *iiORg,

R being loweralkenyl or loweralkynyl', R is o H yJORs and R is loweralkyl, loweralkenyl, loweralkynyl, lowerhaloalkyl or cyclopropylmethyl, with the limitation that each R cannot be ethyl when R is ethyl.

2. A compound in accordance with claim 1 wherein R, is H, R is 3. A compound in accordance with claim 2 wherein each R and R are loweralkyl.

4. A compound in accordance with claim 3 wherein R and R each are ethyl.

I I UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION 9 PATENT NO. 3,869,492

DATED March 4, I975 INV4ENTOR(S) John Hans Biel and Irwin L. Klundt It is certified that error appears in the aboveidentified patent and that said Letters Patent Q are hereby corrected as shown below:

Column 4, within the table showing Examples 3 9, under "Found" heading, under "0'', delete "40.389 and substitute therefor "40.48-- V I Signed and Seal-ed this Q [55 AL} Arrest:

RUTH C. MASON C. MARSHALL DANN r Arresting Officer (mnmixsimwr nflarenls um! Trudvmurks 

1. A COMPOUND OF THE FORMULA
 2. A compound in accordance with claim 1 wherein R1 is H, R2 is
 3. A compound in accordance with claim 2 wherein each R3 and R4 are loweralkyl.
 4. A compound in accordance with claim 3 wherein R3 and R4 each are ethyl. 